128735640 has 384 divisors, whose sum is σ = 505440000. Its totient is φ = 28062720.

The previous prime is 128735639. The next prime is 128735671. The reversal of 128735640 is 46537821.

128735640 is a `hidden beast` number, since 1 + 2 + 8 + 7 + 3 + 5 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 128735595 and 128735604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2181931 + ... + 2181989.

It is an arithmetic number, because the mean of its divisors is an integer number (1316250).

Almost surely, 2^128735640 is an apocalyptic number.

128735640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128735640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252720000).

128735640 is an abundant number, since it is smaller than the sum of its proper divisors (376704360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128735640 is a wasteful number, since it uses less digits than its factorization.

128735640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 128735640 is about 11346.1729230609. The cubic root of 128735640 is about 504.9320432688.

The spelling of 128735640 in words is "one hundred twenty-eight million, seven hundred thirty-five thousand, six hundred forty".